'apodium' originates from Greek, specifically the word 'apodion', where the prefix 'a-' meant 'without' and 'pous' (root 'pod-') meant 'foot'.

'apodion' passed into Late/Medieval Latin and Medieval scientific Latin as 'apodium', and was later adopted into modern English usage; the classical/Latin plural form is 'apodia'.

Initially it meant 'without a foot' in a literal sense; over time it became a technical term in anatomy/biology for organisms or structures lacking feet, retaining the core sense but narrowing to technical use.